Photosynthesis
From Wikipedia, a free encyclopedia written in simple English for easy reading.
Photosynthesis is a process used by plants, some protists, and some bacteria to create energy. It creates glucose and oxygen from carbon dioxide and water. Officially, the formula for photosynthesis is CO2 (carbon dioxide) + H2O (water) = CH2O (glucose) + O2 (oxygen). Cells use it to create ATP from ADP and NADPH from NADP.
[edit] Summary of the process
Photosynthesis begins when light hits a leaf. Each cell in the leaf has little organelles (small organs) called chloroplasts. Inside the chloroplasts are even smaller things called thylakoids. Individual photons of light hit pigments in the thylakoid membrane and begin the process of photosynthesis. The light activates an enzyme that splits water molecules. In other words, H2O → 2H- + O. The splitting of the water molecule activates an electron chain while giving off oxygen. The excited electron chain goes through a carrier protein that, when activated, lets protons enter the cell. However, the protons can not get out, and therefore the pressure builds up inside of the cell. To lower the pressure, another carrier protien lets the protons out, and at the same time uses the energy generated by the escaping proton to fix a phosphate group to an ADP molecule. This makes ATP. After this, the electron chain continues to a hydrogen-fixing enzyme that fixes hydrogen to NADP molecules. When excited by the electron, the enzyme fixes a hydrogen atom to an NADP molecule to form NADPH. While this is happening, the hydrogen and oxygen atoms released bind with the broken up carbon dioxide molecules to form glucose (CH2O). This glucose is later used in cellular respiration to form more ATP...
[edit] Outside factors affecting Photosynthesis
Many things have been proven to change how effective or fast photosynthesis is done by plants. Photosynthesis can only occur between 32-95 degrees F (0-50 degrees C), and is most effective at room temperature (72 degrees F, 25 degrees C). Photosynthesis does not work at night or during cloudy days, because not enough light hits the plants.
